feat(es/parser): Enforce orders of override and async (#1670)

Co-authored-by: 강동윤 <kdy1997.dev@gmail.com>

ecmascript/parser/src/parser/class_and_fn.rs

@@ -716,7 +716,13 @@ impl<'a, I: Tokens> Parser<I> {
         {
             // handle async foo(){}
 
-            let is_override = is_override || self.parse_ts_modifier(&["override"])?.is_some();
+            if self.parse_ts_modifier(&["override"])?.is_some() {
+                is_override = true;
+                self.emit_err(
+                    self.input.prev_span(),
+                    SyntaxError::TS1029(js_word!("override"), js_word!("async")),
+                );
+            }
 
             let is_generator = eat!(self, '*');
             let key = self.parse_class_prop_name()?;

ecmascript/parser/tests/typescript-errors/class/override-with-async/input.ts

@@ -0,0 +1,3 @@
+class C extends B {
+  async override fetch() {}
+}

ecmascript/parser/tests/typescript-errors/class/override-with-async/input.ts.stderr

@@ -0,0 +1,6 @@
+error: 'override' modifier must precede 'async' modifier.
+ --> $DIR/tests/typescript-errors/class/override-with-async/input.ts:2:9
+  |
+2 |   async override fetch() {}
+  |         ^^^^^^^^
+